Seafood gumbo

Again, I quadrupled this recipe for the wedding.

1 cup vegetable oil
1 cup flour
1 ½ cups chopped onions
1 cup chopped celery
1 cup chopped bell peppers
1 lb alligator sausage and/or crawfish sausage
1 lb crawfish tail meat
1 lb medium shrimp
1/2 lb extra-large head and shell on shrimp
1 ½ teaspoon salt
½ teaspoon cayenne (but I ended up using much, much more)
3 bay leaves
6 cups shrimp stock
1 lb chicken meat, cut into chunks
1 tablespoon file powder or 1 cup sliced okra
1 tablespoon each paprika, garlic powder, salt, oregano, thyme, pepper (but I ended up using much, much more)

Combine oil and flour in large cast-iron Dutch oven, over medium heat. STIR CONSTANTLY AND EVENLY for 20-25 minutes, until flour/oil mixture becomes the color of chocolate. This is a dark roux. If you stop stirring, the flour will burn and you will have to start all over again. Once the roux is the proper color, add onions, celery and bell peppers and continue stirring 4-5 minutes. Add sausage, bay leaves and spices. Continue to stir 4-5 minutes. Add shrimp stock, stir until well combined. Bring to boil, reduce to medium-low. Cook uncovered, stirring occasionally, 20 to 30 minutes. Add okra or file powder and cook five minutes. At the very last minute, add the crawfish and the shrimp. Cook one minute, turn the heat off, let sit for one additional minute, or until the seafood is just cooked through. Serve over rice, with fresh parsley and chopped green onions.